error 512

[pgas37]

Raspberrypy V3
Domoticz v 3.8153
RFXcom433e

in wiki smartscript there are some Pir-switch examples
=====================================================
-- ~/domoticz/scripts/lua/script_device_PIRs.lua

commandArray = {}

tc=next(devicechanged)
v=tostring(tc)
if (v:sub(1,3) == 'PIR') then
c=v:sub(4)
commandArray[c] = 'On'
tmess = c..' On - time 0'
print(tmess)
end

return commandArray
==============================
this script returns with an error:2017-12-13 15:52:52.254 Error: Error executing script command (/home/pi/domoticz/scripts/lua/script_device_PIRs.lua). returned: 512

Can anyone help?

thanks
Paul